Lighting unit



May 19, 1931. A. Y. DODGE, I 1,805,690 r LiGl-ITING UNIT Filed Jan. 10. 1929 f Pm ad May 19, 1931' 1 UNITED STATES.

- 1r I Y. DODGE, OF SOUTH BEND,

- men'rgme um;

'hpplicatlon filed Januar a, me. Beriai m. eaten.

My invention relates toelectric lamps. One of the objects of my invention is to improve the light distribution of electric lamps of the'type comprising a trans arent bulband a filament housed in said bul A further object of my invention is to improve the light distribution of electric bulbs used in connection with concave reflectors as in headlight construction.

Further objects will appear from the description and claim. r In the drawings, in which an embodiment of my invention is shown,

Figure 1 is an axial section through a par abolic reflector showing the bulb in position;

Fig. 2 is an enlarged view of the bulb shown in Fig. 1;

Fig. 3 1s a side view of the bulb, part being broken away. to show the axial vertical section; Fig. 4 is a front view of the bulb; and

Fig. 5 is a bottom view of the bulb. Referring to the drawings in detail, the

construction shown thereon comprises a parabolic reflector 1 and an electric lamp 2 mounted therein with the li ht center 3 at or near the focus of the para 019. so that the light rays A from the source falling on the reflector are reflected therefrom in substantially parallel rays B to give a concentrated beam. The lamp base 4 and its connection with the socket portion 5 of the reflector may he of any usual orsuitable construction.

horizontal, and in such installations there is usuall a large proportion of the light from the 40 through the open front of the reflector which serves very little useful purpose and which,

I in fact, is often harmful in that it causes a disagreeable and dangerous glare, and decreases the visibility o the driven,

5 In order to make use of this light; which is In certain installations such as headlights for automobiles the axis of the lamp may be lament wh1ch escapes forwardly.

otherwise practically waste, and avoidthis disagreeable and dangerous glare, the glass enclosing bulb 6 is provided at its forward end with a lens formation-7' of suflicient extent to intercept substantially. all of the li ht -6 rays from the light source which do not all. on the main parabolic reflector 1 and which lie above a horizontalplane throughthe light source. This lens may be so designed as to lessen the divergence of the rays falling thereon so as to cause them to emerge in a substantially horizontal direction and so as to materially lessen the lateral divergence as shown at C in Figures 1 and 2. As the rays lying below the-horizontal lane through the 6 light source are not in a irection to cause glare and are in a direction to be useful, the lower edge 8 of the lens is so designed as to lie substantially in a" horizontally plane through the light source so that the rays be- 85 low this plane are not diverted. As shown in Fi 4, the lens is semi-circular in shape, with its upper semi-circular edge lying substantially in the surface of a cone having its center at the light source and its base defined by the circumference of the opening in the concave reflector, as indicated at D in Fig.1.

While I have described but one embodiment of my invention, it is obvious that manymodifications therein may occur to those skilled in the art, and I desire, therefore, that my invention be limited only by the scope of the appended claim and by t e prior art.

I claim: I 0' A light project "g apparatus comprising a concave reflector and an electric lamp in front of said concave reflector said lamp comprising a transparent bulb and a concentrated .light source in said bulb said bulb having a lens integral therewith or lessening the'diver' ence of the re s from the light. source falhng thereon, sai lens projectin forward 1y from fltlge front of the bulb an having a convex frontfa'ce above the horizontal plane 5a 2 2 aaoaaao 3 through the light source and having a lower crescent shaped surface lyin substantially in said horizontal plane, sai lens having a greater refractive power vertically than hori- 5 zontally whereby the upward rays striking the lens are refracted to a substantially hori-. zontal direction while the laterally directed re s still diver after being refracted.-

n witness w ereof, I have hereunto subscribed my name.

' ADIEL Y. DODGE. 

